The present invention relates to generally an ink-jet printing head and more particularly an ink-jet printing head of the type in which the length between a nozzle hole at one end of an ink distribution tube and an ink inlet at the other end thereof (to be referred to as "a resonant distance" for brevity in this specification at which the ink in the ink manifold is resonated) can be adjusted by adjusting the position of a reflecting plate disposed adjacent to the ink inlet.
In general, the bell-and-spigot joint has been used for connecting the ink manifold to an ink supply tube. In some cases, a resonance adjusting tube is interconnected between the ink distribution tube and the ink supply tube and a reflecting plate or the like with a center ink passage hole is inserted into the resonance adjusting tube from its end to be connected to the ink supply tube. The distance between the nozzle hole of the ink manifold and the ink passage hole of the reflecting plate is a resonance distance. The fine adjustment of the resonance distance is made by cutting off the resonance adjusting tube. This means two steps must be carried out alternately. That is, in a first step, an error between a predetermined resonance distance and an overall axial length of the ink distribution tube and the resonance adjusting tube must be measured and in a second step, the resonance adjusting tube must be cut off so that the overall axial length becomes equal to the resonance distance. Therefore, the assembly of ink-jet printing heads is time-consuming and cumbersome. In addition, if an error is negative; that is, if an overall axial length is shorter than a predetermined resonance distance, a short resonance adjusting tube must be discarded with the resultant decrease in yield. Futhermore, two steps must be added for liquid-tightly sealing the joints between the ink distribution tube and the resonance adjusting tube and between the resonance adjusting tube and the ink supply tube. Thus, the prior art ink-jet printing head needs many component parts and many assembly steps and is, therefore, expensive in cost.